1. Field of the Invention
The present invention relates to a projector and an adjustment method of the projector that may incorporate a three-panel projector. According to an embodiment of the present invention, the registration deviation is corrected by interpolation arithmetic processing after the signal level of a color signal is corrected so that the signal level is in proportion to the brightness level displayed on a screen, so that the registration deviation can be simply corrected with high accuracies so as to reduce the deterioration in image quality in comparison with the past.
2. Description of the Related Art
In production lines of the three-panel projector, the alignment of an optical system and a liquid crystal display panel has been mechanically adjusted for registration. Namely, as shown FIG. 4, a three-panel projector 1 drives transmission liquid crystal display panels 2R, 2G, and 2B for red, green, and blue with three-color signals, respectively, as well as it divides an illumination beam emitted from a predetermined light source into three-color illumination beams with an optical system such as a dichroic prism. The three-panel projector 1 admits the three-color illumination beams onto the transmission liquid crystal display panels 2R, 2G, and 2B and modulates them so as to produce three-color image beams LR, LG, and LB, respectively. The three-panel projector 1 projects the image beams LR, LG, and LB onto a screen 3 via a predetermined optical system so as to display color images on the screen 3.
Thus, on the screen 3 of the three-panel projector 1, if the three-color images 4R, 4G, and 4B due to the respective image beams LR, LG, and LB are not precisely overlapped with each other and displayed, the registration deviation would be generated. Then, in the production lines, the transmission liquid crystal display panels 2R, 2G, and 2B are fixed with an adhesive for preventing the registration deviation after their alignment is mechanically adjusted to correct the registration deviation.
Referring to FIG. 4, if the blue-image 4B is deviated in registration relative to the green-image 4G in the horizontal or vertical direction, for example, the mounting position of the transmission liquid crystal display panel 2B is displaced by the angle corresponding to its registration deviation in the horizontal or vertical direction so as to correct the registration deviation. Alternatively, if the blue-image 4B is obliquely inclined to deviate relative to the green-image 4G, the mounting position of the transmission liquid crystal display panel 2B is rotated by its registration deviation so as to correct the registration deviation.
As for such registration, a method for preventing the registration deviation due to mechanical impact is proposed in Japanese Unexamined Patent Application Publication No. H07-287204. An electrical registration adjusting method is also proposed in Japanese Unexamined Patent Application Publication No. 2004-229195, in which a display device is driven via a memory and the address written on the memory is controlled. Also, a measuring method of the convergence that is the registration in a cathode ray tube device is proposed in Japanese Unexamined Patent Application Publication No. R05-236516.
When the registration is adjusted by mechanically aligning the mounting positions of the optical system and the liquid crystal display panel, the work may require a time and the deviation cannot be perfectly corrected.
A method for solving the problems may include the technique disclosed in Japanese Unexamined Patent Application Publication No. 2004-229195; however, in this method, the registration deviation can be corrected only in one-pixel units and also only in the horizontal or vertical direction.